Uppercase Converter
Convert text to UPPERCASE instantly, for free.
This tool runs entirely in your browser. Your files are never uploaded to a server.
What this tool does
Converts any text to UPPERCASE, using JavaScript's standard Unicode case mapping — every letter it recognizes as having an uppercase form is converted, non-letters are left unchanged.
How to use it
Type or paste text into the box; the uppercase result appears below and updates as you type. Buttons above the box switch to six other case styles — lowercase, Title Case, Capitalized Case, Sentence case, aLtErNaTiNg cAsE, and iNVERSE cASE — without leaving the page.
Worked example
"Hello World" becomes "HELLO WORLD", and accented letters are handled too: "café" becomes "CAFÉ", keeping the acute accent on the É.
Method
The conversion calls JavaScript's built-in String.prototype.toUpperCase(), which applies the Unicode default case-mapping algorithm — the same one used throughout modern browsers — rather than a locale-specific one.
Language-specific cases to know
Because the mapping is locale-independent, some conversions differ from what a specific language expects. German ß becomes SS (for example, straße becomes STRASSE) since there's no traditional single uppercase eszett in this mapping, and that conversion can't be reversed back to ß by lowercasing. Turkish is affected too: a lowercase dotted i (as in istanbul) becomes a plain dotless I (ISTANBUL) here, rather than the dotted İ that Turkish orthography expects — for Turkish-specific casing, a dedicated Turkish-locale tool is needed.
Limitations
This uppercases the whole text uniformly; it doesn't offer AP/Chicago-style title casing or sentence-aware capitalization — use the Title Case or Sentence case buttons above for those. It also can't restore an original mixed-case string once it's been uppercased, since case information is discarded in the conversion.
Privacy and processing
The conversion runs entirely in your browser using JavaScript. Nothing you type is uploaded or stored.
Frequently Asked Questions
- Does this handle accented letters and other languages?
- Yes — it uses JavaScript's Unicode-aware toUpperCase(), so accented Latin letters (café → CAFÉ), Cyrillic, Greek and many other scripts convert correctly. A few language-specific cases, like Turkish dotted i, don't match that language's own casing rules.
- Can I turn the uppercase text back into the original?
- No — uppercasing discards information, such as which letters were originally capitalized, and in German ß becomes SS with no way to tell it apart from an original SS. Keep a copy of your original text if you need it later.
- Why does istanbul become ISTANBUL instead of İSTANBUL?
- JavaScript's default case mapping isn't Turkish-aware: a dotted lowercase i always becomes a dotless capital I here, not the dotted İ that Turkish expects. This is a well-known limitation often called the "Turkish I problem."
- What other case styles can I switch to?
- Lowercase, Title Case, Capitalized Case, Sentence case, aLtErNaTiNg cAsE, and iNVERSE cASE are all available from the buttons above the text box, using the same input.